I have designed and built a custom imx6 board. Design is similar to the reference diagram. The power supply is running off a NXP PF1510. The device is driven of the USB power rail (5.0V, stable supply). USB_OTG1 is connected to USB TypeA connector.
Only OTG1 being used
Connected to USB Type A
BOOT MODE Selector switch, ONOFF Left floating. POR with two option - driven by PMIC / Left floating
https://i.stack.imgur.com/0bPEb.pngXTAL connected
THE PROBLEM STATEMENT
When connected to the PC (MAC/Linux/Windows) the device is not detected (should come up as HID).
Despite everything cannot get the device to be detected on USB. I would appreciated any ideas anyone can give.
Thank you (Do not have an oscilloscope)
Hi Harkirat
one can check board schematic using
Hardware Development Guide for the i.MX 6UltraLite Applications Processor
pay attention to 24MHz clock accuracy (it may affect usb detection) and power supplies
ripples (<5%). Try with several computers. Just for test one can prolong POR up to 1 sec.
Best regards
igor
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Igor,
Thanks for your reply.
The voltage rails are
VBUS - 5.145V (PMIC supply)
SW1 - 1.389V
SW2 - 1.355V
SW3 - 3.340V
VLDO1 - 1.802V
VLDO2 - Unconnected
VLDO3 - 3.296
VSNVS - 3.041V
DDR_VREF - 0.676V
on power on with POR_B floating POR_B - 3.309V
Tried powering up the board with POR_B pulled down released after > 5 sec - No detection
Tried pulling down POR_B after 10 sec of PMIC power on (initially with POR_B floating) - no detection
XTAL
ABS07-32.768kHZ-9-T
ESR - 70kOhm
Load Cap - 9pF and board cap is 9pF +/- 0.1pF
ASDMB-24.000MHZ-XY-T
Stability +/- 10ppm (not checked)
Output load 10kOhm
Load Cap - 15pF
Board Cap 15pF (1%)
Deviation - 2.2M registor to GND for XTALI bias not externally adjustable
Q: Based on the schematic i have shared, are the board caps correct?
one can check board schematic using
Hardware Development Guide for the i.MX 6UltraLite Applications Processor
Done that.the only deviations are
Since BOOT_MODE[1:0] have an on chip pulldown (Page 12) are not connected externally to GND at 00
Kept Floating
USB_OTG1_ID - Type A connector not microusb
USB_OTG1_OC
USB_OTG_PWR
I am severely hampered due to lack of oscilloscope, short of that is there anything else i can try?
Again, any ideas are appreciated.
Regards,